Stock-Based Compensation - Black-Scholes Option-Pricing Model Assumptions Used to Calculate Fair Value of Employee Stock Options (Detail)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Average risk-free interest rate	1.60%	1.60%	0.90%
Dividend yield	0.00%	0.00%	0.00%
Average volatility factor	50.80%	51.60%	61.20%
Average weighted average expected life	5 years 3 months 18 days	5 years 2 months 12 days	5 years 2 months 12 days